1. Field of the Invention
This invention relates to communication systems and methods of operation. More particularly, the invention relates to a distributed information system (DIS), e.g., the Internet, and methods of operation providing telephony with callback for subscribers in a Public Switched Telephone System.
2. Description of Prior Art
In the current environment it is possible to place voice calls over a data network such as the Internet. Such calls were originally restricted to using one personal computer to call another personal computer, with no ability to call a regular telephone in a Public Switched Telephone Network (PSTN). Recently, Voice Gateways have been added to the Internet which bridge between the data network and the voice networks in the PSTN. However, such Voice Gateways do not support standard enhanced telephony features such as returning the last unanswered call or callback. Complicating this problem is the fact that Internet users are often given temporary addresses and identifications by their Internet Service Providers (ISP) using a feature called Dynamic Host Protocol (DHCP). Thus, returning a call from a PSTN phone to an Internet user contains different problems depending on whether the user is still logged on at the originally assigned ISP address or if the user has logged off, and that ISP address has been reassigned to a different user. Accordingly, a need exists to expand Telephone service on the Internet to interconnect users and subscribers in a PSTN while providing users and subscribers with callback without impact from DHCP.
Prior art related to telephone service and the Internet includes the following:
PCT published application WO 97/16916, published May 9, 1997, and filed Nov. 1, 1995, discloses a method and apparatus for communicating audio information over a computer network. A standard telephone connected to a PSTN can communicate with any other PSTN connected telephone using a computer network such as the Internet as the transmission facility instead of conventional telephone transmission facilities. The caller dials the number of an access port or the computer network and transmits the number of the called party when connected to the port. The port receives the number of the called party and establishes a two-way, full duplex communication link via the computer network to a corresponding remote access port or specialized computer system in the vicinity of the called party. The port at the receiving end is connected to the local PSTN in the region of the called party and uses the local PSTN to connect the call to the called party. The communication protocols used by the computers on the internet to communicate information include TCP (Transmission Control Protocol) and UDP (User Datagram Protocol). Both the TCP and UDP protocols are built on top of a lower layer protocol known as the IP (Internet Protocol). IP is used to format and route TCP and UDP messages.
U.S. Pat. No. 5,425,091 issued Jun. 13, 1995, discloses automatic customer callback implemented directly into service logic of an Advanced Intelligent Network (AIN). The AIN includes a central office switch which is in communication with a service control point, at least one calling party, and at least one called party. The AIN components preferably communicate with one another through Transaction Capability Application Part (TCAP) signalling protocol and are directed for use in a AIN 0.2 network. An adjunct processor such as an Intelligent Peripheral (IP)) is in communication with the central office switch. In operation, digits dialed by the calling party are collected as well as the calling party""s telephone number. If the called party is busy, the calling party activates the automatic customer callback service, the subscriber telephone line will be monitored to detect an idle condition. Once this condition is detected, a call may be originated from the adjunct processor to the subscriber whereupon a message may be played for receipt by the subscriber advising the same of the need to callback the calling party who activated the automatic customer callback.
U.S. Pat. No. 5,351,237 issued Sep. 27, 1994, discloses a plurality of Local Area Networks (LAN) connected to an Integrated Services Digital Network (ISDN) via a plurality of routers, each of which includes a table for routing information. Each router sets local router information and main/sub-setting information. Each sub-router sets main-router information which is written in the table. Each sub-router sends an inquiry packet including the local router information to the main router. The main router receives the inquiry packet, enters the local router information in the table, and sends to each sub-router a reply packet including the local router information stored in the table. Each sub-router receives a reply packet and enters the local router information in the table. On the basis of the router information stored in the table each router renews routing information.
None of the prior art, alone or in combination, shows or suggests a distributed information system, e.g., the Internet, with expanded telephone service including callback between the users and subscribers in a PSTN without impact from DHCP protocol problems.
An object of the invention is a distributed information system and method of operation with improved telephone service between users and subscribers in a PSTN.
Another object of the invention is a distributed information system, e.g., the Internet, and method of operation with improved telephone service including callback.
Another object is a distributed information system and method of operation with improved telephone service between users and subscribers in a PSTN without impact from dynamic host protocol problems and the system.
Another object is a distributed information system and method of operation with improved telephone service in displaying to a call originator the fact that a call has been queued in a return call machine at the called party.
Another object is a distributed information system and method of operation with improved telephone service in generating call profiles to solve the problem of dynamic host protocols.
Another object of the invention is a distributed information system and method of operation with improved telephone service indicating a return call to a calling party as a returned call.
These and other objects, features and advantages are achieved in a distributed information system, e.g., the Internet, adapted for telephony including callback for unanswered telephone calls between a user and a subscriber in a Public Switch Telephone Network. A calling station in the distributed information system (DIS) and a called station in the Public Switch Telephone Network (PSTN) are each connected to the DIS through a local and remote service provider, respectively. Each provider includes a voice gateway and a callback server. A telephone call originated at the calling station by a calling party is processed by the local service provider and the local callback server generates a control message which accompanies the telephone call. The remote service provider when the return call is initiated, even though the address of the called party and the DIS may have changed, the remote callback server sends a message to the local callback server which identifies the latest address for the called party and extends the return call to the calling party. If the calling party is busy or unavailable, the roles of the local remote callback servers are reversed. The remote (formerly the local) callback server stores the message and initiates a return reply message when the called party (formerly the calling party) generates the message.